Prosthetic Heart Valve Having Identifiers for Aiding in Radiographic Positioning

ABSTRACT

A prosthetic heart valve having identifiers for aiding in radiographic positioning is described.

FIELD OF THE INVENTION

The present invention relates generally to prosthetic heart valves, andspecifically to techniques for accurately positioning such valves duringimplantation procedures.

BACKGROUND OF THE INVENTION

Aortic valve replacement in patients with severe valve disease is acommon surgical procedure. The replacement is conventionally performedby open heart surgery, in which the heart is usually arrested and thepatient is placed on a heart bypass machine. In recent years, prostheticheart valves have been developed which are implanted using minimallyinvasive procedures such as transapical or percutaneous approaches.These methods involve compressing the prosthesis radially to reduce itsdiameter, inserting the prosthesis into a delivery tool, such as acatheter, and advancing the delivery tool to the correct anatomicalposition in the heart. Once properly positioned, the prosthesis isdeployed by radial expansion within the native valve annulus.

While these techniques are substantially less invasive than open heartsurgery, the lack of line-of-sight visualization of the prosthesis andthe native valve presents challenges, because the physician cannot seethe actual orientation of the prosthesis during the implantationprocedure. Correct positioning of the prostheses is achieved usingradiographic imaging, which yields a two-dimensional image of the viewedarea. The physician must interpret the image correctly in order toproperly place the prostheses in the desired position. Failure toproperly position the prostheses sometimes leads to device migration orto improper functioning. Proper device placement using radiographicimaging is thus critical to the success of the implantation.

PCT Publication WO 05/002466 to Schwammenthal et al., which is assignedto the assignee of the present application and is incorporated herein byreference, describes prosthetic devices for treating aortic stenosis.

PCT Publication WO 06/070372 to Schwammenthal et al., which is assignedto the assignee of the present application and is incorporated herein byreference, describes a prosthetic device having a single flow fieldtherethrough, adapted for implantation in a subject, and shaped so as todefine a fluid inlet and a diverging section, distal to the fluid inlet.

US Patent Application Publication 2006/0149360 to Schwammenthal et al.,which is assigned to the assignee of the present application and isincorporated herein by reference, describes a prosthetic deviceincluding a valve-orifice attachment member attachable to a valve in ablood vessel and including a fluid inlet, and a diverging member thatextends from the fluid inlet, the diverging member including a proximalend near the fluid inlet and a distal end distanced from the proximalend. A distal portion of the diverging member has a largercross-sectional area for fluid flow therethrough than a proximal portionthereof.

US Patent Application Publication 2005/0197695 to Stacchino et al.,describes a cardiac-valve prosthesis adapted for percutaneousimplantation. The prosthesis includes an armature adapted for deploymentin a radially expanded implantation position, the armature including asupport portion and an anchor portion, which are substantially axiallycoextensive with respect to one another. A set of leaflets is coupled tothe support portion. The leaflets can be deployed with the armature inthe implantation position. The leaflets define, in the implantationposition, a flow duct that is selectably obstructable. The anchorportion can be deployed to enable anchorage of the cardiac-valveprosthesis at an implantation site.

The following patents and patent application publications, are set forthas background:

U.S. Pat. No. 6,312,465 to Griffin et al.

U.S. Pat. No. 5,908,451 to Yeo

U.S. Pat. No. 5,344,442 to Deac

U.S. Pat. No. 5,354,330 to Hanson

US Patent Application Publication 2004/0260389 to Case et al.

U.S. Pat. No. 6,730,118 to Spencer et al.

U.S. Pat. No. 7,018,406 to Seguin et al.

U.S. Pat. No. 7,018,408 to Bailey et al.

U.S. Pat. No. 6,458,153 and US Patent Application Publication2003/0023300 to Bailey et al.

US Patent Application Publication 2004/0186563 to Lobbi

US Patent Application Publication 2003/0130729 to Paniagua et al.

US Patent Application Publication 2004/0236411 to Sarac et al.

US Patent Application Publication 2005/0075720 to Nguyen et al.

US Patent Application Publication 2006/0058872 to Salahieh et al.

US Patent Application Publication 2005/0137688 to Salahieh et al.

US Patent Application Publication 2005/0137690 to Salahieh et al.

US Patent Application Publication 2005/0137691 to Salahieh et al.

US Patent Application Publication 2005/0143809 to Salahieh et al.

US Patent Application Publication 2005/0182483 to Osborne et al.

US Patent Application Publication 2005/0137695 to Salahieh et al.

US Patent Application Publication 2005/0240200 to Bergheim

US Patent Application Publication 2006/0025857 to Bergheim et al.

US Patent Application Publication 2006/0025855 to Lashinski et al.

US Patent Application Publication 2006/0047338 to Jenson et al.

US Patent Application Publication 2006/0052867 to Revuelta et al.

US Patent Application Publication 2006/0074485 to Realyvasquez

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SUMMARY OF THE INVENTION

In some embodiments of the present invention, a prosthetic heart valveprosthesis comprises three commissural posts to which are coupled aprosthetic valve. The commissural posts are shaped so as definetherethrough respective openings that serve as radiographic identifiersduring an implantation procedure. During the procedure, the valveprosthesis, including the commissural posts, is initially collapsedwithin a delivery tube. Before expanding the valve prosthesis, aphysician uses radiographic imaging, such as x-ray fluoroscopy, toprovide visual feedback that aids the physician in rotationally aligningthe commissural posts with respective native commissures of a nativesemilunar valve. The identifiers strongly contrast with the rest of thecommissural posts and the valve prosthesis, which comprise a radiopaquematerial. Without such identifiers, it is generally difficult tothree-dimensionally visually distinguish the commissural posts from oneanother and from the rest of the valve prosthesis, because theradiographic imaging produces a two-dimensional representation of thethree-dimensional valve prosthesis. When the valve prosthesis is in acollapsed state, the elements thereof overlap in a two-dimensional imageand are generally indistinguishable.

In some embodiments of the present invention, the physician selects oneof the commissural posts having a radiographic identifier, and attemptsto rotationally align the selected post with one of the nativecommissures, such as the commissure between the left and right coronarysinuses. Because the radiographic image is two-dimensional, all of theposts appear in the image as though they are in the same plane. Thephysician thus cannot distinguish between two possible rotationalpositions of the posts: (1) the desired rotational position, in whichthe selected post faces the desired native commissure, and (2) arotational position 180 degrees from the desired rotational position, inwhich the selected post faces the side of the native valve opposite thedesired native commissure. For example, if the desired native commissureis the commissure between the left and right coronary sinuses, inposition (2) the post is rotationally aligned with the noncoronarysinus, although this undesired rotation is not apparent in theradiographic image.

To ascertain whether the posts are in rotational position (1) or (2),the physician slightly rotates the valve prosthesis. If the radiographicidentifier on the selected post appears to move in the radiographicimage in the same direction as the rotation, the selected post iscorrectly rotationally aligned in the desired position (1). If, on theother hand, the radiographic identifier appears to move in the directionopposite the direction of rotation, the selected post is incorrectlyrotationally aligned in position (2). To correct the alignment, thephysician may rotate the valve prosthesis approximately 60 degrees ineither direction, thereby ensuring that one of the two other posts isnow rotationally aligned in position (1). (The valve prosthesistypically has three-fold rotational symmetry, such that rotation of 60degrees is sufficient to properly align one of the posts with theselected native commissure, and the prosthesis need not be rotated afull 180 degrees.) In these embodiments, the openings through the poststhat define the radiographic identifiers may assume any convenientshape, such as a slit.

In some embodiments of the present invention, the openings that definethe radiographic identifiers are shaped to be reflection-asymmetricalong respective post axes that are generally parallel with a centrallongitudinal axis of the prosthesis when the posts assume theircollapsed position. For example, the identifiers may be shaped as one ormore reflection-asymmetric characters, such as numbers or letters of thealphabet, e.g., B, C, D, E, etc. The physician can thus readily identifythe true orientation of the selected post that appears to berotationally aligned with the selected native commissure. If theidentifier on the selected post appears in the correct left-rightorientation, the selected post is aligned in the desired position (1).If, on the other hand, the identifier appears as the mirror image of itscorrect left-right orientation, the selected post is incorrectlyrotationally aligned in position (2). To correct the alignment, thephysician may rotate the valve prosthesis approximately 60 degrees ineither direction, thereby ensuring that one of the two other posts isnow rotationally aligned in position (1).

There is therefore provided, in accordance with an embodiment of thepresent invention, apparatus including a valve prosthesis, whichincludes a prosthetic heart valve, and three or more commissural posts,to which the prosthetic heart valve is coupled. The posts are arrangedcircumferentially around a central longitudinal axis of the valveprosthesis, and are configured to assume a collapsed position prior toimplantation of the prosthesis, and an expanded position upon theimplantation of the prosthesis. One or more of the commissural posts areprovided with respective radiographic identifiers that are shaped to bereflection-asymmetric about respective post axes that are generallyparallel with the central longitudinal axis when the posts assume thecollapsed position.

For some applications, the radiographic identifiers have the shape ofone or more reflection-asymmetric characters.

In an embodiment, the one or more of the commissural posts are shaped todefine respective openings therethrough which define the respectiveradiographic identifiers. Alternatively, the radiographic identifiersinclude a material having a first radiopacity that is different from asecond radiopacity of the commissural posts, which material is coupledto the one or more of the commissural posts.

For some applications, the valve prosthesis includes exactly threecommissural posts.

There is further provided, in accordance with an embodiment of thepresent invention, a method including:

providing a valve prosthesis that includes a prosthetic heart valve, andthree or more commissural posts, to which the prosthetic heart valve iscoupled, which posts are arranged circumferentially around a centrallongitudinal axis of the valve prosthesis, and are configured to assumea collapsed position prior to implantation of the prosthesis, and anexpanded position upon the implantation of the prosthesis, and at leastone of which commissural posts is provided with a radiographicidentifier;

while the posts assume the collapsed position, placing, via a bloodvessel of the subject, the valve prosthesis at least partially in aheart of a subject in a vicinity of a native heart valve having nativecommissures;

generating a fluoroscopic image of the native commissures and valveprosthesis; and

rotationally aligning the at least one of the commissural posts with oneof the native commissures using the radiographic identifier visible inthe image.

In an embodiment, rotationally aligning includes rotating the valveprosthesis; observing whether the at least one of the commissural postsappears to move in the image in the same direction that the valveprosthesis is rotated, or in an opposite direction; and, if the at leastone of the commissural posts appears to move in the image in theopposite direction, rotating the valve prosthesis to correct arotational alignment, of the valve prosthesis.

For some applications, the valve prosthesis includes exactly threecommissural posts, and is configured to have three-fold rotationalsymmetry, and rotating the valve prosthesis to correct the rotationalalignment includes rotating the valve prosthesis approximately 60degrees.

In an embodiment, the radiographic identifier is shaped to bereflection-asymmetric about a post axis of the at least one of thecommissural posts, which axis is generally parallel with the centrallongitudinal axis when the posts assume the collapsed position. For someapplications, the radiographic identifier has the shape of areflection-asymmetric character.

For some applications, rotationally aligning includes observing in theimage whether the radiographic identifier appears in a correctleft-right orientation, and, if the radiographic identifier does notappear in the correct left-right orientation, rotating the valveprosthesis to correct a rotational alignment of the valve prosthesis.For some applications, the valve prosthesis includes exactly threecommissural posts, and is configured to have three-fold rotationalsymmetry, and rotating the valve prosthesis to correct the rotationalalignment includes rotating the valve prosthesis approximately 60degrees.

In an embodiment, the at least one of the commissural posts is shaped todefine an opening therethrough which defines the radiographicidentifier. Alternatively, the radiographic identifier includes amaterial having a first radiopacity that is different from a secondradiopacity of the at least one of the commissural posts, which materialis coupled to the at least one of the commissural posts.

For some applications, the one of the native commissures is a nativecommissure (C_(RL)) between a left coronary sinus and a right coronarysinus, and rotationally aligning includes rotationally aligned the oneof the commissural posts with the C_(RL).

There is still further provided, in accordance with an embodiment of thepresent invention, a method including:

providing a valve prosthesis that includes a prosthetic heart valve, andthree or more commissural posts, to which the prosthetic heart valve iscoupled, which posts are arranged circumferentially around a centrallongitudinal axis of the valve prosthesis, and are configured to assumea collapsed position prior to implantation of the prosthesis, and anexpanded position upon the implantation of the prosthesis;

while the posts assume the collapsed position, placing, via a bloodvessel of the subject, the valve prosthesis at least partially in aheart of a subject in a vicinity of a native heart valve having nativecommissures;

generating a fluoroscopic image of the native commissures and valveprosthesis; and

rotationally aligning the at least one of the commissural posts with oneof the native commissures by:

rotating the valve prosthesis,

observing whether the at least one of the commissural posts appears tomove in the image in the same direction that the valve prosthesis isrotated, or in an opposite direction, and

if the at least one of the commissural posts appears to move in theimage in the opposite direction, rotating the valve prosthesis tocorrect a rotational alignment of the valve prosthesis.

For some applications, the valve prosthesis includes exactly threecommissural posts, and is configured to have three-fold rotationalsymmetry, and rotating the valve prosthesis to correct the rotationalalignment includes rotating the valve prosthesis approximately 60degrees.

There is additionally provided, in accordance with an embodiment of thepresent invention, apparatus including a valve prosthesis, whichincludes:

a prosthetic heart valve;

a support structure, which includes a first material having a firstradiopacity; and

one or more radiographic identifiers, which include a second materialhaving a second radiopacity different from the first radiopacity, andwhich are coupled to the support structure at respective locations.

In an embodiment, the radiographic identifiers are shaped to bereflection-asymmetric about respective identifier axes that aregenerally parallel with a central longitudinal axis of the valveprosthesis.

For some applications, the identifiers are arranged circumferentiallyaround a central longitudinal axis of the valve prosthesis.

For some applications, the support structure is shaped so as to define abulging proximal skirt, and the identifiers are coupled to the skirt.

For some applications, the support structure includes three or morecommissural posts, to which the prosthetic heart valve is coupled, whichposts are arranged circumferentially around a central longitudinal axisof the valve prosthesis, the locations at which the identifiers arecoupled to the support structure are not on the posts, and the locationsare radially aligned with the posts.

For some applications, the support structure includes three or morecommissural posts, to which the prosthetic heart valve is coupled, whichposts are arranged circumferentially around a central longitudinal axisof the valve prosthesis, and the locations at which the identifiers arecoupled to the support structure are on the posts.

The present invention will be more fully understood from the followingdetailed description of embodiments thereof, taken together with thedrawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of a fully-assembled valveprosthesis, in accordance with an embodiment of the present invention;

FIGS. 2A and 2B are schematic illustrations of a collapsible outersupport structure and a collapsible inner support structure,respectively, prior to assembly together into the valve prosthesis ofFIG. 1, in accordance with an embodiment of the present invention;

FIG. 3 is a schematic illustration of a subject undergoing a transapicalor percutaneous valve replacement procedure, in accordance with anembodiment of the present invention;

FIG. 4 shows an exemplary fluoroscopic view generated with afluoroscopic system during a valve replacement procedure, in accordancewith an embodiment of the present invention;

FIG. 5 shows an exemplary ultrasound view generated with an ultrasoundprobe during a valve replacement procedure, in accordance with anembodiment of the present invention;

FIGS. 6A and 6B are schematic and fluoroscopic views, respectively, ofthe valve prosthesis of FIG. 1 in a collapsed position in a catheter, inaccordance with an embodiment of the present invention;

FIGS. 7A and 7B are schematic illustrations of the valve prosthesis ofFIG. 1 in situ upon completion of transapical and retrograde transaorticimplantation procedures, respectively, in accordance with respectiveembodiments of the present invention;

FIGS. 7C-7E are schematic illustrations of an implantation procedure ofan alternative configuration of the valve prosthesis of FIG. 1, inaccordance with an embodiment of the present invention;

FIGS. 8A-B are schematic illustrations of the valve prosthesis of FIG. 1positioned within the aortic root, in accordance with an embodiment ofthe present invention;

FIG. 9 is a flow chart that schematically illustrates a method forascertaining whether the valve prosthesis of FIG. 1 or FIGS. 7C-E areproperly rotationally aligned with the native commissures, in accordancewith an embodiment of the present invention and

FIGS. 10A and 10B are schematic illustrations of reflection-asymmetricradiographic identifiers on commissural posts of the valve prosthesis ofFIG. 1 or FIGS. 7C-E, in accordance with respective embodiments of thepresent invention.

DETAILED DESCRIPTION OF EMBODIMENTS

FIG. 1 is a schematic illustration of a fully-assembled valve prosthesis10, in accordance with an embodiment of the present invention.Typically, valve prosthesis 10 comprises exactly three commissural posts11, arranged circumferentially around a central longitudinal axis 13 ofvalve prosthesis 10. Valve prosthesis 10 further comprises a prostheticdistal valve 104 coupled to coupled to commissural posts 11. Valve 104typically comprises a pliant material 105. Pliant material 105 of valve104 is configured to collapse inwardly (i.e., towards centrallongitudinal axis 13) during diastole, in order to inhibit retrogradeblood flow, and to open outwardly during systole, to allow blood flowthrough the prosthesis. For some applications, valve prosthesis 10comprises a collapsible inner support structure 12 that serves as aproximal fixation member, and a collapsible outer support structure 14that serves as a distal fixation member.

One or more (e.g., all) of commissural posts 11 are shaped so as definetherethrough respective openings 16 that serve as radiographicidentifiers during an implantation procedure, as described hereinbelowwith reference to FIGS. 3-8B. The openings may assume any convenient,shape, for example, slits, as shown in FIGS. 1, 2A-B, and 6A-B. In someembodiments, the openings are shaped to be reflection-asymmetric alongrespective post axes generally parallel with central longitudinal axis13 of prosthesis 10 when the posts assume their collapsed position, asdescribed hereinbelow with reference to FIGS. 10A-B. For someapplications, in addition to serving as the radiographic identifiers,openings 16 are used for coupling valve 104 to support structures 12 and14. Although pliant material 105 of valve 104 at least partially fillsopenings 16, the material is substantially more radiolucent thancommissural posts 11, and thus does not reduce the radiographicvisibility of the radiographic identifiers. Alternatively, one or moreof posts 11 do not necessarily define openings 16, and the one or moreposts instead comprise radiographic identifiers comprising a materialhaving a radiopacity different from (greater or less than) theradiopacity of posts 11, such as gold or tantalum.

Valve prosthesis 10 is configured to be placed in a native diseasedvalve of a subject, such as a native stenotic aortic or pulmonary valve,using a minimally-invasive approach, such as a beating heart transapicalprocedure, such as described hereinbelow with reference to FIG. 7A, or aretrograde transaortic procedure, such as described hereinbelow withreference to FIG. 7B. As used in the present application, including inthe claims, a “native semilunar valve” is to be understood as including:(a) native semilunar valves that include their native leaflets, and (b)native semilunar valves, the native leaflets of which have beensurgically excised or are otherwise absent.

Reference is made to FIG. 2A, which is a schematic illustration ofcollapsible outer support structure 14 prior to assembly with innersupport structure 12, in accordance with an embodiment of the presentinvention. In this embodiment, outer support structure 14 is shaped soas to define a plurality of distal diverging strut supports 20, fromwhich a plurality of proximal engagement arms 22 extend radially outwardin a proximal direction. Engagement arms 22 are typically configured tobe at least partially disposed within aortic sinuses of the subject,and, for some applications, to engage and/or rest against floors of theaortic sinuses, and to apply an axial force directed toward a leftventricle of the subject. Outer support structure 14 comprises asuitable material that allows mechanical deformations associated withcrimping and expansion of valve prosthesis 10, such as, but not limitedto, nitinol or a stainless steel alloy (e.g., AISI 316).

Reference is made to FIG. 23, which is a schematic illustration ofcollapsible inner support structure 12 prior to assembly with outersupport structure 14, in accordance with an embodiment of the presentinvention. For some applications, inner support structure 12 is shapedso as to define a plurality of distal diverging inner struts 30, and abulging proximal skirt 32 that extends from the struts. A proximalportion 34 of proximal skirt 32 is configured to engage a leftventricular outflow tract (LVOT) of the subject and/or periannulartissue at the top of the left ventricle. A relatively narrow throatsection 36 of proximal skirt 32 is configured to be positioned at avalvular annulus of the subject, and to engage the native valveleaflets. Inner support structure 12 comprises, for example, nitinol, astainless steel alloy, another metal, or another biocompatible material.

Reference is again made to FIG. 1. Inner and outer support structures 12and 14 are assembled together by placing outer support structure 14 overinner support structure 12, such that cuter strut supports 20 arealigned with, and typically support, respective inner struts 30, andengagement arms 22 are placed over a portion of proximal skirt 32. Innerstruts 30 and outer strut supports 20 together define commissural posts11.

Although exactly three commissural posts 11 are shown in the figures,for some applications valve prosthesis 10 comprises fewer or more posts11, such as two posts 11, or four or more posts 11.

Typically, valve prosthesis 10 further comprises a graft covering 106which is coupled to proximal skirt 32, such as by sewing the coveringwithin the skirt (configuration shown in FIG. 1) or around the skirt(configuration not shown). Inner support structure 12 thus defines acentral structured body for flow passage that proximally terminates in aflared inlet (proximal skirt 32) that is configured to be seated withinan LVOT immediately below an aortic annulus/aortic valve. For someapplications, graft covering 106 is coupled at one or more sites topliant material 105.

In an embodiment of the present invention, a portion valve prosthesis 10other than commissural posts 11, e.g., proximal skirt 32, is shaped soas to define openings 16 that serve as radiographic identifiers.Alternatively or additionally, the commissural posts or this otherportion of the prosthesis comprise radiographic identifiers comprising amaterial having a radiopacity different from (greater or less than) theradiopacity of other portions of the prosthesis. For some applications,the radiographic identifiers are radially aligned with commissural posts11.

FIG. 3 is a schematic illustration of a subject 200 undergoing atransapical or percutaneous valve replacement procedure, in accordancewith an embodiment of the present invention. A fluoroscopy system 210comprises a fluoroscopy source 213, a fluoroscopy detector 212, and amonitor 214. Fluoroscopy source 213 is positioned over subject 200 so asto obtain a left anterior oblique (LAO) projection of between 30 and 45,such as between 30 and 40, degrees with a 30-degree cranial tilt (fororthogonal projection of the annulus). Typically, imaging is enhancedusing an ultrasound probe 216.

FIG. 4 shows an exemplary fluoroscopic view 220 generated withfluoroscopic system 210 during a valve replacement procedure, inaccordance with an embodiment of the present invention. In the view, aright coronary sinus (RCS) 222 and a left coronary sinus (LCS) 224 arevisible, as are the respective coronary arteries that originate from thesinuses. The view also shows a commissure 226 between the right and leftsinuses (C_(RL)). RCS 222, LCS 224, and C_(RL) 226 serve as clearanatomical landmarks during the replacement procedure, enabling thephysician to readily ascertain the layout of the aortic root.

FIG. 5 shows an exemplary ultrasound view 230 generated with ultrasoundprobe 216 during a valve replacement procedure, in accordance with anembodiment of the present invention. In the view, the RCS, LCS, andnon-coronary sinus (N) are visible. The orientation of view 230 can beseen with respect to a sternum 232 and a spine 234, as well as withrespect to fluoroscopy detector 212.

FIGS. 6A and 6B are schematic and fluoroscopic views, respectively, ofvalve prosthesis 10 in a collapsed position in a catheter 300, inaccordance with an embodiment of the present invention. In thisembodiment, openings 16 are shaped as slits. As can be seen in FIG. 6B,these slits are clearly visible with fluoroscopy.

Reference is made to FIGS. 7A and 7B, which are schematic illustrationsof valve prosthesis 10 in situ upon completion of transapical andretrograde transaortic implantation procedures, respectively, inaccordance with respective embodiments of the present invention.

In the transapical procedure, as shown in FIG. 7A, an introducerovertube or trocar 150 is inserted into a left ventricular apex 156using a Seldinger technique. Through this trocar, a delivery catheter(not shown in the figure) onto which collapsed valve prosthesis 10 ismounted, is advanced into a left ventricle 357 where its motion isterminated, or through left ventricle 357 until the distal end of adilator (not shown) passes native aortic valve leaflets 358. Forexample, apex 356 may be punctured using a standard Seldinger technique,and a guidewire may be advanced into an ascending aorta 360. Optionally,a native aortic valve 340 is partially dilated to about 15-20 mm (e.g.,about 16 mm), typically using a standard valvuloplasty balloon catheter.(In contrast, full dilation would be achieved utilizing dilation of 20mm or more.) Overtube or trocar 350 is advanced into the ascendingaorta. Overtube or trocar 350 is pushed beyond aortic valve 340 suchthat the distal end of overtube or trocar 350 is located above thehighest point of native aortic valve 340. The dilator is removed whileovertube or trocar 350 remains in place with its distal end locatedabove aortic valve 340. Alternatively, the procedure may be modified sothat overtube or trocar 350 is placed within left ventricle 350 andremains within the left ventricle throughout the entire implantationprocedure. Valve prosthesis 10 is advanced through the distal end ofovertube or trocar 350 into ascending aorta 360 distal to nativeleaflets 358.

Valve prosthesis 10, typically while still within the catheter, isrotated to align arms 22 with aortic sinuses 364, as describedhereinbelow with reference to FIGS. 8A-B or FIGS. 10A-B. After theprosthesis is properly rotationally aligned, withdrawal of the cathetercauses engagement arms 22 to flare out laterally to an angle which istypically predetermined by design, and to open in an upstream direction.Gentle withdrawal of the delivery catheter, onto which prosthesis 10with flared-out arms 22 is mounted, causes the arms to slide into aorticsinuses 364. Release of the device from the delivery catheter causes alower inflow portion of prosthesis 10 to unfold and press against theupstream side of native leaflets 358, thereby engaging with the upstreamfixation arms in the aortic sinuses. The upstream fixation arms serve ascounterparts to the lower inflow portion of the prosthesis in amechanism that locks the native leaflets and the surrounding periannulartissue for fixation.

For some applications, prosthesis 10 is implanted using techniquesdescribed with reference to FIGS. 5A-C in U.S. application Ser. No.12/050,628, filed Mar. 18, 2008, entitled, “Valve suturing andimplantation procedures,” which is incorporated herein by reference.

In the retrograde transaortic procedure, as shown in FIG. 7B, valveprosthesis 10 is positioned in a retrograde delivery catheter 450. Aretrograde delivery catheter tube 451 of catheter 450 holds engagementarms 22, and a delivery catheter cap 452 holds proximal skirt 32 (notshown). A guidewire 490 is transaortically inserted into left ventricle357. Optionally, stenotic aortic valve 340 is partially dilated to about15-20 mm (e.g., about 16 mm), typically using a standard valvuloplastyballoon catheter. Retrograde delivery catheter 450 is advanced overguidewire 490 into ascending aorta 360 towards native aortic valve 340.Retrograde delivery catheter 450 is advanced over guidewire 490 untildelivery catheter cap 452 passes through native aortic valve 340partially into left ventricle 357.

Valve prosthesis 10, typically while still within the catheter, isrotated to align arms 22 with aortic sinuses 364, as describedhereinbelow with reference to FIGS. 8A-B or FIGS. 10A-B. Retrogradedelivery catheter tube 451 is pulled back (in the direction indicatedschematically by an arrow 455), while a device stopper (not shown)prevents valve prosthesis 10 within tube 451 from being pulled back withtube 451, so that engagement arms 22 are released and flare outlaterally into the sinuses. At this stage of the implantation procedure,proximal skirt 32 of prosthesis 10 remains in delivery catheter cap 452.

Delivery catheter cap 452 is pushed in the direction of the apex of theheart, using a retrograde delivery catheter cap shaft (not shown) thatpasses through tube 451 and prosthesis 10. This advancing of cap 452frees proximal skirt 32 to snap or spring open, and engage the innersurface of the LVOT. Retrograde delivery catheter tube 451 is furtherpulled back until the rest of valve prosthesis 10 is released from thetube. Retrograde delivery catheter tube 451 is again advanced over theshaft toward the apex of the heart, until tube 451 rejoins cap 452.Retrograde delivery catheter 450 and guidewire 490 are withdrawn fromleft ventricle 357, and then from ascending aorta 360, leavingprosthesis 10 in place.

For some applications, prosthesis 10 is implanted using techniquesdescribed with reference to FIGS. 9A-G in above-mentioned U.S.application Ser. No. 12/050,628.

Reference is made to FIGS. 7C-7E, which are schematic illustrations ofan implantation procedure of an alternative configuration of valveprosthesis 10, in accordance with an embodiment of the presentinvention. In this configuration, valve prosthesis 10 does not compriseproximal engagement arms 22. Even without these arms, which rest in thesinus floors and thus may aid in properly rotationally aligning theprosthesis, the techniques described herein achieve proper alignment ofthe prosthesis. For some applications, valve prosthesis 10 is configuredas described in a U.S. provisional patent application filed on even dateherewith, entitled, “Prosthetic heart valve for transfemoral delivery,”which is assigned to the assignee of the present application and isincorporated herein by reference.

FIG. 7C shows valve prosthesis 10 positioned in retrograde deliverycatheter 450, which is advanced into left ventricle 357 over guidewire490. Valve prosthesis 10, typically while still within the catheter, isrotated to align commissural posts 11 with the native commissures, asdescribed hereinbelow with reference to FIGS. 8A-B or FIGS. 10A-B. Afterthe prosthesis is properly rotationally aligned, withdrawal of thecatheter causes expansion of the frame of prosthesis, as shown in FIG.7D. FIG. 7E shows this configuration of prosthesis 10 positioned withinthe aortic root (viewed from the aorta). The frame of the prosthesis isshaped so as to define distal support members 492, which extend in adownstream direction (i.e., they do not extend into the floors of theaortic sinuses). Distal support elements 492 are configured to restagainst the downstream portion of the aortic sinuses upon implantationof valve prosthesis 10, so as to provide support against tilting of theprosthesis with respect to a central longitudinal axis of theprosthesis. As can be seen in FIG. 7E, commissural posts 11 of the valveprosthesis are rotationally aligned with native commissures 494.

Reference is made to FIGS. 8A-B, which are schematic illustrations ofvalve prosthesis 10 positioned within the aortic root (viewed from theaorta), in accordance with an embodiment of the present invention. Asdescribed above with reference to FIGS. 7A-B, during an implantationprocedure, a delivery catheter is inserted into an overtube and advanceduntil the distal end of commissural posts 11 arrive near the end of theovertube. For configurations of valve prosthesis 10 that includeproximal engagement arms 22, the arms are still within the catheter. Toproperly rotationally align posts 11 with the native commissures, thephysician rotates valve prosthesis 10 under fluoroscopy until one 496 ofcommissural posts 11 is aligned with one of the native commissures, suchas commissure 226 between the right and left sinuses (C_(RL)). In anattempt to achieve such a rotational position, the physician rotates theprosthesis until one of openings 16 that serve as radiographicidentifiers is centered from the viewpoint of the fluoroscopic LAOprojection such as shown in FIG. 6B (openings 16 are not visible fromthe view of FIGS. 8A-B). The other two commissural posts 11 flank thecentered post.

At this stage of the procedure, because the radiographic image istwo-dimensional and all of the posts appear in the image as though theyare in the same plane, it is difficult for the physician to ascertainwhether commissural post 496 selected for alignment is:

-   -   (1) in the desired rotational position, closer to fluoroscopy        detector 212 (FIG. 3) than are the other two commissures, and        thus properly aligned with the C_(RL) 226, as shown in FIG. 8A;        or    -   (2) farther away from the fluoroscopy detector than are the        other two posts, rotated 180 degrees from the desired rotational        position, as shown in FIG. 8B. In this rotational orientation,        centered post 496 projects itself onto C_(RL) 226, but actually        faces the noncoronary sinus (N) away from the fluoroscopy        detector, such that valve prosthesis 10 is misaligned by 60        degrees (because the prosthesis typically has three-fold        rotational symmetry).

Reference is made to FIG. 9, which is a flow chart that schematicallyillustrates a method 500 for ascertaining whether the posts are in thefirst or second possible rotational position, in accordance with anembodiment of the present invention. At an initial rotation step 502,the physician slightly rotates valve prosthesis 10. At an apparentrotation check step 504, the physician ascertains whether theradiographic identifier on the selected post appears to move in theradiographic image in the same direction as the rotation. If theidentifier appears to move in the same direction as the rotation, thephysician ascertains that the selected post is correctly rotationallyaligned in the desired position (1) (after the physician slightlyrotates the prosthesis in the opposite direction to return it to itsinitial position), at a proper alignment ascertainment step 506. If, onthe other hand, the radiographic identifier appears to move in thedirection opposite the direction of rotation, the physician ascertainsthat the selected post is incorrectly rotationally aligned in position(2), at an improper alignment ascertainment step 508. To correct thealignment, the physician rotates the valve prosthesis approximately 60degrees in either direction, thereby ensuring that one of the two otherposts is now rotationally aligned in position (1), at an alignmentcorrection step 510. (The valve prosthesis typically has three-foldrotational symmetry, such that rotation of 60 degrees is sufficient toproperly align one of the posts with the selected native commissure, andthe prosthesis need not be rotated a full 180 degrees.) For example,assume that at initial rotation step 502 the physician rotates theprosthesis clockwise, as viewed from the aorta. If the valve prosthesisis properly aligned, the radiographic identifier on the selected postappears to move toward the LCS at apparent rotation check step 504. Oncethe valve prosthesis is properly aligned, commissural posts 11 arereleased from the catheter, as well as proximal engagement arms 22, forconfigurations of the prosthesis that include such arms, at acommissural post release step 512. In these embodiments, openings 16through posts 11 that define the radiographic identifiers may assume anyconvenient shape, such as a slit.

In an embodiment of the present invention, this technique forrotationally aligning posts 11 with the native commissures is used foraligning a valve prosthesis that does not include radiographicidentifiers. Instead of using such identifiers, the physician observeselements of the prosthesis that are discernable in the radiographicimages, such as posts 11.

FIGS. 10A and 10B are schematic illustrations of reflection-asymmetricradiographic identifiers 600 on commissural posts 11, in accordance withrespective embodiments of the present invention. Identifiers 600 may beused with both the configuration of valve prosthesis 10 describedhereinabove with reference to FIG. 1, and that described hereinabovewith reference to FIGS. 7C-E. Openings 16 that define radiographicidentifiers 600 are shaped to be reflection-asymmetric along respectivepost axes 604 that are generally parallel central longitudinal axis 13of prosthesis 10 when the posts assume their collapsed position. Forexample, as shown in FIG. 10A, identifiers 600 may be shaped as one ormore reflection-asymmetric letters of the alphabet, such as B, C, D, E,etc, or numbers. Alternatively, the identifier may be shaped as anyreflection-symmetric symbol, such as the inverted elongated L shown inFIG. 10B. The physician can thus readily identify the true orientationof the selected post that appears to be rotationally aligned with theselected native commissure. If the identifier on the selected postappears in the correct left-right orientation, the selected post isaligned in the desired position (1), as described hereinabove withreference to FIGS. 8A-B. If, on the other hand, the identifier appearsas the mirror image of its correct left-right orientation, the selectedpost is incorrectly rotationally aligned in position (2) as describedhereinabove with reference to FIGS. 8A-B. To correct the alignment, thephysician rotates the valve prosthesis approximately 60 degrees ineither direction, thereby ensuring that one of the two other posts isnow rotationally aligned in position (1).

For some applications, such as shown in FIG. 10A, at least one ofcommissural posts 11 is shaped so as to define bothreflection-asymmetric radiographic identifier 600 and anotherreflection-symmetric shape 610, such as a slit. For example, such a slitmay have a mechanical purpose, such as coupling valve 104 to supportstructures 12 and 14, as described hereinabove with reference to FIG. 1.Alternatively, the physician may use reflection-symmetric shape 610 forrotational orientation as described hereinabove with reference to FIGS.8A-B in the event that reflection-asymmetric radiographic identifiers600 are not be clearly visible in the radiographic image during aparticular implantation procedure.

For some applications, reflection-asymmetric radiographic identifiers600 are not defined by openings 16, but instead comprise a materialhaving a radiopacity different from (greater or less than) theradiopacity of other portions of the posts. For some applications, aportion of valve prosthesis 10 other than commissural posts 11 comprisesradiographic identifiers 600 (whether defined by openings, or comprisinga material having a different radiopacity).

For some applications, techniques described herein are performed incombination with techniques described in a U.S. provisional patentapplication filed on even date herewith, entitled, “Prosthetic heartvalve for transfemoral delivery,” which is assigned to the assignee ofthe present application and is incorporated herein by reference.

The scope of the present invention includes embodiments described in thefollowing applications, which are assigned to the assignee of thepresent application and are incorporated herein by reference. In anembodiment, techniques and apparatus described in one or more of thefollowing applications are combined with techniques and apparatusdescribed herein:

-   -   U.S. patent application Ser. No. 11/024,908, filed Dec. 30,        2004, entitled, “Fluid flow prosthetic device,” which issued as        U.S. Pat. No. 7,201,772;    -   International Patent Application PCT/IL2005/001399, filed Dec.        29, 2005, entitled, “Fluid flow prosthetic device,” which        published as PCT Publication WO 06/070372;    -   International Patent Application PCT/IL2004/000601, filed Jul.        6, 2004, entitled, “Implantable prosthetic devices particularly        for transarterial delivery in the treatment of aortic stenosis,        and methods of implanting such devices,” which published as PCT        Publication WO 05/002466, and U.S. patent application Ser. No.        10/563,384, filed Apr. 20, 2006, in the national stage thereof,        which published as US Patent Application Publication        2006/0259134;    -   U.S. Provisional Application 60/845,728, filed Sep. 19, 2006,        entitled, “Fixation member for valve”;    -   U.S. Provisional Application 60/852,435, filed Oct. 16, 2006,        entitled, “Transapical delivery system with ventriculo-arterial        overflow bypass”;    -   U.S. application Ser. No. 11/728,253, filed Mar. 23, 2007,        entitled, “Valve prosthesis fixation techniques using        sandwiching”;    -   International Patent Application PCT/IL2007/001237, filed Oct.        16, 2007, entitled, “Transapical delivery system with        ventriculo-arterial overflow bypass,” which published as PCT        Publication WO 2008/047354; and/or    -   U.S. application Ser. No. 12/050,628, filed Mar. 18, 2008,        entitled, “Valve suturing and implantation procedures.”

It will be appreciated by persons skilled in the art that the presentinvention is not limited to what has been particularly shown anddescribed hereinabove. Rather, the scope of the present inventionincludes both combinations and subcombinations of the various featuresdescribed hereinabove, as well as variations and modifications thereofthat are not in the prior art, which would occur to persons skilled inthe art upon reading the foregoing description.

1. Apparatus comprising a valve prosthesis, which comprises: aprosthetic heart valve; and three or more commissural posts, to whichthe prosthetic heart valve is coupled, which posts are arrangedcircumferentially around a central longitudinal axis of the valveprosthesis, and are configured to assume a collapsed position prior toimplantation of the prosthesis, and an expanded position upon theimplantation of the prosthesis, wherein one or more of the commissuralposts are provided with respective radiographic identifiers that areshaped to be reflection-asymmetric about respective post axes that aregenerally parallel with the central longitudinal axis when the postsassume the collapsed position.
 2. The apparatus according to claim 1,wherein the radiographic identifiers have the shape of one or morereflection-asymmetric characters.
 3. The apparatus according to claim 1,wherein the one or more of the commissural posts are shaped to definerespective openings therethrough which define the respectiveradiographic identifiers.
 4. The apparatus according to claim 1, whereinthe radiographic identifiers comprise a material having a firstradiopacity that is different from a second radiopacity of thecommissural posts, which material is coupled to the one or more of thecommissural posts.
 5. The apparatus according to claim 1, wherein thevalve prosthesis comprises exactly three commissural posts.
 6. A methodcomprising: providing a valve prosthesis that includes a prostheticheart valve, and three or more commissural posts, to which theprosthetic heart valve is coupled, which posts are arrangedcircumferentially around a central longitudinal axis of the valveprosthesis, and are configured to assume a collapsed position prior toimplantation of the prosthesis, and an expanded position upon theimplantation of the prosthesis, and at least one of which commissuralposts is provided with a radiographic identifier; while the posts assumethe collapsed position, placing, via a blood vessel of the subject, thevalve prosthesis at least partially in a heart of a subject in avicinity of a native heart valve having native commissures; generating afluoroscopic image of the native commissures and valve prosthesis; androtationally aligning the at least one of the commissural posts with oneof the native commissures using the radiographic identifier visible inthe image.
 7. The method according to claim 6, wherein rotationallyaligning comprises: rotating the valve prosthesis; observing whether theat least one of the commissural posts appears to move in the image inthe same direction that the valve prosthesis is rotated, or in anopposite direction; and if the at least one of the commissural postsappears to move in the image in the opposite direction, rotating thevalve prosthesis to correct a rotational alignment of the valveprosthesis.
 8. The method according to claim 7, wherein the valveprosthesis includes exactly three commissural posts, and is configuredto have three-fold rotational symmetry, and wherein rotating the valveprosthesis to correct the rotational alignment comprises rotating thevalve prosthesis approximately 60 degrees.
 9. The method according toclaim 6, wherein the radiographic identifier is shaped to bereflection-asymmetric about a post axis of the at least one of thecommissural posts, which axis is generally parallel with the centrallongitudinal axis when the posts assume the collapsed position.
 10. Themethod according to claim 9, wherein the radiographic identifier has theshape of a reflection-asymmetric character.
 11. The method according toclaim 9, wherein rotationally aligning comprises: observing in the imagewhether the radiographic identifier appears in a correct left-rightorientation; and if the radiographic identifier does not appear in thecorrect left-right orientation, rotating the valve prosthesis to correcta rotational alignment of the valve prosthesis.
 12. The method accordingto claim 11, wherein the valve prosthesis includes exactly threecommissural posts, and is configured to have three-fold rotationalsymmetry, and wherein rotating the valve prosthesis to correct therotational alignment comprises rotating the valve prosthesisapproximately 60 degrees.
 13. The method according to claim 6, whereinthe at least one of the commissural posts is shaped to define an openingtherethrough which defines the radiographic identifier.
 14. The methodaccording to claim 6, wherein the radiographic identifier comprises amaterial having a first radiopacity that is different from a secondradiopacity of the at least one of the commissural posts, which materialis coupled to the at least one of the commissural posts.
 15. The methodaccording to claim 6, wherein the one of the native commissures is anative commissure (C_(RL)) between a left coronary sinus and a rightcoronary sinus, and wherein rotationally aligning comprises rotationallyaligned the one of the commissural posts with the C_(RL).
 16. A methodcomprising: providing a valve prosthesis that includes a prostheticheart valve, and three or more commissural posts, to which theprosthetic heart valve is coupled, which posts are arrangedcircumferentially around a central longitudinal axis of the valveprosthesis, and are configured to assume a collapsed position prior toimplantation of the prosthesis, and an expanded position upon theimplantation of the prosthesis; while the posts assume the collapsedposition, placing, via a blood vessel of the subject, the valveprosthesis at least partially in a heart of a subject in a vicinity of anative heart valve having native commissures; generating a fluoroscopicimage of the native commissures and valve prosthesis; and rotationallyaligning the at least one of the commissural posts with one of thenative commissures by: rotating the valve prosthesis, observing whetherthe at least one of the commissural posts appears to move in the imagein the same direction that the valve prosthesis is rotated, or in anopposite direction, and if the at least one of the commissural postsappears to move in the image in the opposite direction, rotating thevalve prosthesis to correct a rotational alignment of the valveprosthesis.
 17. The method according to claim 16, wherein the valveprosthesis includes exactly three commissural posts, and is configuredto have three-fold rotational symmetry, and wherein rotating the valveprosthesis to correct the rotational alignment comprises rotating thevalve prosthesis approximately 60 degrees.
 18. Apparatus comprising avalve prosthesis, which comprises: a prosthetic heart valve; a supportstructure, which comprises a first material having a first radiopacity;and one or more radiographic identifiers, which comprise a secondmaterial having a second radiopacity different from the firstradiopacity, and which are coupled to the support structure atrespective locations.
 19. The apparatus according to claim 18, whereinthe radiographic identifiers are shaped to be reflection-asymmetricabout respective identifier axes that are generally parallel with acentral longitudinal axis of the valve prosthesis.
 20. The apparatusaccording to claim 18, wherein the identifiers are arrangedcircumferentially around a central longitudinal axis of the valveprosthesis.
 21. The apparatus according to claim 18, wherein the supportstructure is shaped so as to define a bulging proximal skirt, andwherein the identifiers are coupled to the skirt.
 22. The apparatusaccording to claim 18, wherein the support structure comprises three ormore commissural posts, to which the prosthetic heart valve is coupled,which posts are arranged circumferentially around a central longitudinalaxis of the valve prosthesis, wherein the locations at which theidentifiers are coupled to the support structure are not on the posts,and wherein the locations are radially aligned with the posts.
 23. Theapparatus according to claim 18, wherein the support structure comprisesthree or more commissural posts, to which the prosthetic heart valve iscoupled, which posts are arranged circumferentially around a centrallongitudinal axis of the valve prosthesis, wherein the locations atwhich the identifiers are coupled to the support structure are on theposts.